Hinge-lock for pivoted arms



May 6, 1958 N. H. GLADSTONE ETAL 2,833,038

HINGE-LOCK FOR PIVOTED ARMS Filed Dec. 11 1953 INVEN ORS v c 9'5 A/AT'HAN H.6LAD51' NE V/ TOR RKIN llT-romvzy.

United States Patent O HINGE-LQCK FOR PIVOTED ARMS Nathan H. Gladstone and Victor Arkin, Los Angeles, Calif.

Application December 11, 1953, Serial No. 397,640

5 Claims. (Cl. 32-23) Our invention relates to a hinged lock for pivoted arms, and more particularly to an automatic locking and unlocking mechanism for a dental standard for supporting the driven hand piece or dental tool when not in use.

The usual contrivances for supporting the hand piece is a hook mounted to the standard from which the hand piece is suspended. In many instances, the dentist will attempt to hook the hand piece, without visual assurance that the hook is securely engaged.

Many attempts have been made to provide a securing means which will avoid the likelihood of accident possible with the hook type appliance.

The important object of-our invention is to provide a latch which will permit the operator to push the hand piece in an outward direction which motion will automatically cause'the hand piece to be securely locked to the dental standard.

Another object is to provide a mechanism which will give the operator an audible and tactile reaction to the completion of the locking movement.

Other objects are to provide a locking action of the aforesaid character which will permit the lock to open and release the hand tool by a simple motion of the tool itself; and to accomplish the foregoing without the visual attention hitherto needed.

These and other objects of our invention are accomplished and our new results obtained as will be apparent from the device described in the following specification,

The customary pivot member 19 has an upstanding arm 11, from which extends a rod 12 carrying at its free end of the conventional reel 13, that controls the movement of the hand piece or drill holder 14, as shown in Fig. l. The handpipe is supported by arm 15 upon the conventional hook 16. Extending from pivot is a second arm or standard 17, from which projects a rod 18 provided with a plate 19, which is drilled to receive a center bolt 20 for mounting a ratchet 21, having projecting pins 22.

A clamp 23 holds the plate 19 against movement. To the plate is mounted a screw 24 from which is connected a spring 25 which is connected at its other end to a pawl 26 which is pivoted at 27 to plate 19. The pawl 26 is provided with a tooth 28 shown in Fig. 2, which engages one of the ratchet notches 29. The ratchet notches comprise shallow gripping notches 29a alternately positioned with deeper release notches 29b. An arcuate strip 30 'ice 2 bolted at 31 to the arm 11, is controlled by guide 32, the movement being limited by stop pin 33, shown in Fig. 1.

As shown in Fig. 2, the latch or strip 30 has a shoulder 34 that is locked with the shoulder or stop 35 of the catch or pawl 26. The position of the locked pawl and strip are here controlled by the shallow gripping notch 29a. This arrangement positively locks the drill holder in an inoperative position.

Mounted on strip 30 is a plate 36, held by screws 37 to the strip. Pivoted as at 38 at one end of plate 36 is an actuator pawl 39 having a jaw 40 which, as shown in Fig. 2 is aligned so as to contact one of the pins 22. When the operator prepares to use the drill, he grips thedrill holder 14 and causes a clockwise motion to arm 11, forcing the actuator pawl 39 to engage a pin '22 to partly rotate ratchet 21, so that a release ratchet notch 29b is moved into position, forcing pawl tooth 28 out of engagement with gripping notch 29a and freeing the strip from the pawl, as shown in Fig. 3.

The actuator pawl 39 pivoted on screw 38 is held in position by a spring 41 fixed at screw 42 to plate 36, and at screw 43 to a plate 44 which is pivoted as at 45 to the actuator pawl 39 which is: partly broken away in Fig. 2, to show its bifurcated construction.

It will be noted that the position of the shoulder 34 of the arcuate strip 30 when the actuator pawl 39 is in the advanced position shown in Fig. l, is a short distance beyond the shoulder 35. Thus the hand piece may be withdrawn this same distance before the shoulder 35 stops the movement of the arcuate strip, as shown in Fig. 2. This play in the motion is permitted to allow the actuator pawl 39 to be advanced again to release the I arcuate strip and allow the hand piece to be operatively positioned as previously described.

In position, the hand piece is free to be moved to an infinite number of extended operative positions.

The mechanism we have provided makes possible the alternate locking and releasing of the arm to which the hand piece is. mounted. The lock 16 may thus be dispensed with.

The mechanism illustrated and described achieves the various objects of our invention. The operator may push the hand piece and associated arm towards the standard until a click is heard which represents the pawl tooth snapping into the ratchet gripping notch under action of' the spring 25. The feel of the actuator pawl rotating the ratchet wheel out of one notch into the other is preliminary to the clicking sound. The hand piece and associated arm will be thus secured in position.

When it is desired to free the hand piece, the partial clockwise motion is followed by the same tactile and audible reaction which precedes the release of the arm and hand piece. Thus it is possible to retract the hand piece or advance the same to operative position without visually inspecting the means of securement.

We have thus described our invention but we desire it understood that it is not confined to the particular forms or uses shown and described, the same being merely illustrative, and that the invention may be carried out in other ways withoutdeparting from the spirit of our invention, and, therefore, we claim broadly the right to employ all equivalent instrumentalities coming within the scope of the appended claims, and by means of which objects of our invention are attained and new results accomplished, as it is obvious that the particular embodiments herein shown and described are only some of the many that can be employed to attain these objects and accomplish these results.

We claim: 1. A dental apparatus comprising a standard member,

pivot means at one end of said standard member, and an arm member connected to said pivot means and freely supported on said standard member; locking means comprising a latch and, a catch, said'latch attached to the arm.

member, said, catch attached to the standard member, said locking means being positioned on said members adjacent said pivot; said latch engaging said catch to. pivotally lock. thev two members together upon a predetermined movement of one member towards the other member, means for releasing the latch from the catch upon a further movement of one member towards the other member, and a guide for applying the latch for insuring engagement with the catch during the locking thereof, said locking means further including a pawl and ratchet wheel rotatable upon the movement of the arm member toward the standard member, to shift the pawl, whereby to lock and unlock the two members.

2. The apparatus of claim 1, wherein the ratchet wheel is provided with pins and the arm member is provided with a catch for engaging the pins to move the ratchet wheel. 7

3. The apparatus of claim 2, wherein the ratchet Wheel is provided with successive notches, alternately variable in depth for successively locking and unlocking the latch.

4. The mechanism of claim 3, wherein said latch carried by the arm member including an arcuate strip having a tooth thereon is controlled by the pawl for controlling the movement of the arm.

5. In a dental apparatus having a standard, an arm mounted on said standard by means of a pivot, a driven hand piece pivotally mounted to said arm for use with a drill, said standard provided, adjacent the pivot, with a ratchet wheel having pins extending therefrom and successive notches alternately variable in depth; a pivotally mounted spring biased pawl having a stop and a References Cited in the file of this patent UNITED STATES PATENTS 2,415,203 Freedman Feb. 4, 1947 FOREIGN PATENTS Germany June 23, 1952 

